The present invention relates in general to MOS devices and, more particularly, to a high gain MOS device with improved frequency response.
MOS devices are commonly used in radio frequency applications such as cellular phones and other communications products. For radio frequency applications it is desirable to obtain higher power gain and improved frequency response than can be obtained in prior art MOS devices.
In MOS devices higher power gain is typically obtained by increasing the transconductance (Gm) of the MOS device. Techniques to improve transconductance generally require advancements in processing technologies, e.g. advances in photolithographic techniques, or advances in thin insulator growth techniques. The increase in Gm is usually accomplished by using a single channel doping implant. The increase in Gm is related to the increase in the internal electric field near the source of the implanted channel. However, in a single channel implant, there is a limit to which this internal electric field may be increased before short channel effect and drain induced barrier lowering occurs.
Hence, a need exists for an improved MOS device for higher power gain and improved radio frequency response while reducing short channel effect and drain induced barrier lowering.